The CAESAR resummation plugin to SHERPA hooks into the event generation framework, facilitating
the process management, and providing access to the COMIX matrix-element generator [1]},
as well as phase-space integration and event-analysis functionalities. The SHERPA framework is also
used to compile all the required higher-order tree-level and one-loop calculations. For the NLO QCD
computations we use the SHERPA implementation of the Catani–Seymour dipole subtraction [2]}
and the interfaces to the RECOLA  [3]}, [4]} and OPENLOOPS  [5]}
one-loop amplitude generators. The plugin implements the building blocks of the CAESAR master formula
Eq. (REF ), along with the necessary expansion in \(\alpha _s\)  used in the matching with fixed-order
calculations. The building blocks are evaluated fully differentially for each Born-level
configuration \(\mathcal {B}_\delta \)  of a given flavour and momentum configuration.Note, for the case of non-additive observables that
feature a non-trivial multiple emission function, we pre-compute \({\cal {F}}\)  numerically and tabulate
its values on a grid for read-out during event generation.
